I use IE8 on brand new OEM machines I’m setting up for people and 10 seconds to open a tab is not out of the ordinary. It might take you 1 second, but the majority of users don’t get anything like that.

I'm on a notebook with a core 2 duo at 2ghz. It's about as typical as you can get for new computers. I just tried opening a tab on an old machine that has Vista and a 1.7ghz celeron and it took 4 seconds. You probably tried opening a tab at startup when the cpu was overloaded by crapware. That's not the fault of IE.

The fact is that any other browser is simply faster than IE8 in every department.

That's not true, IE8 is faster for Flash heavy websites, especially when compared to Firefox. Non-IE browsers are choked much quicker by Flash ads. But that is beside the point since I was taking issue when your claim that it has poor JS performance. IE8 doesn't have poor JS performance, it just scores below the other browsers in synthetic benchmarks. Those benchmarks do not translate into equally distant performance gains when it comes to real world browsing.

I do believe that Chrome is overall faster than IE which is why I use it. But IE8 is not this slow monstrosity that you make it out to be. Most people wouldn't be able to tell the difference between IE8 and FF 3.5 in a blind rendering test. There was a time when FF was clearly faster than IE but those days are over. The bandwidth is the real bottleneck when it comes to browsing.

You seem to have a grudge against IE which keeps you from judging it objectively.

As for FF OS X? The trick is to write in FF OS X and fix for Windows, not the other way around. FF/Mac’s rendering is much more accurate (even supporting better ligatures than Webkit).

You can speak of accuracy and tricks all day if you want but at the end of the day a lot of rendering leeway is left to the browsers which leaves subjective experiences and in my experience Firefox is the absolute worst when it comes to cross platform consistency. Silly me I guess for assuming that a program with the same name and version number that follows "standards" wouldn't require constant checking for platform bugs.

I actually spent more time accounting for FF OSX/Win bugs than IE bugs, but partly because we didn't support IE6. The webkit browsers were the best to work with and the few quirks they had weren't show stopping. My advice is to test in FF OSX last since they are such a small percentage of all visitors. If it was a personal site I wouldn't even bother. Mozilla treats their OSX build like an ugly stepchild and I'm not keen on encouraging its use.